In May 2005, CDC
received reports of four solid organ-transplant recipients with unknown
illness. All were infected with lymphocytic choriomeningitis virus (LCMV)
from a common organ donor. Three of the four organ recipients died from
LCMV infection.

Epidemiologic investigation
traced the source of the virus to a pet hamster recently purchased by
the donor from a pet store in Rhode Island. LCMV testing of other rodents
at the pet store identified three other LCMV-infected rodents (two hamsters
and a guinea pig). All four pet rodents had been supplied by a single
distributor, MidSouth Distributors in Ohio. During this investigation,
it was determined that LCMV-infected pet rodents might have been transported
from the Ohio facility to pet stores in the northeastern and midwestern
United States as early as February 2005.

Where
does the virus come from?

The primary host
of LCMV is the common house mouse (Mus musculus). LCMV is not normally
found in pet rodents, such as hamsters, gerbils, and guinea pigs. However,
pet rodents can become infected after being in contact with wild house
mice in breeding facilities, pet stores, or homes. People have become
infected from contact with LCMV-infected hamsters.

Humans can develop
LCMV infection from exposure to urine, droppings, saliva, or nesting material
of infected rodents. LCMV infection can also occur when these materials
are inhaled or directly introduced into broken skin or into the nose,
eyes, or mouth, and possibly by a bite from an infected animal.

What
are the symptoms of LCMV in people?

Adults with normal
immune systems can be infected with LCMV without symptoms, or they may
develop a mild illness with symptoms that may include the following: fever,
lack of appetite, muscle aches, headache, chills, nausea, and vomiting.
Some people may have meningitis (inflammation of the brain covering) approximately
7-15 days after the start of fever. People with weakened immune systems
may have more severe or fatal illness when infected with LCMV.

Women who become
infected with LCMV during pregnancy may
have spontaneous abortion, or their baby may have severe birth defects,
including congenital hydrocephalus (fluid on the brain), chorioretinitis
(inflammation of the eye), blindness, or mental retardation. The proportion
of developmental defects caused by LCMV is not known.

Can
LCMV spread from one person to another?

A pregnant woman
who becomes infected can pass the LCMV infection to her unborn baby; in
addition, LCMV can be spread through organs transplanted from an infected
donor. With the exception of these situations, there is no documented
evidence of person-to-person transmission.

Which
pet stores have LCMV-infected rodents?

Rodents and other
pets from any pet store pose some risk of transmitting certain
infectious diseases and should be handled appropriately. For more information
on how to reduce the risk of infectious diseases from your pet, please
see the CDC Healthy
Pets Web site.

Should
I get rid of my pet hamster or other rodent?

Persons who are
not pregnant and who have healthy immune systems are at very low risk
for any serious illness associated with LCMV. The probability of any one
rodent being infected is low. The greatest risk of infection for a pet
owner is likely to occur soon after purchase of a pet rodent. Thus, most
exposures have likely already occurred for existing owners, and continued
ownership of the rodent will not likely result in substantial added risk.
Persons with further concerns about their pets should seek guidance from
a veterinarian. Women who are pregnant or planning to become pregnant,
or persons who have impaired immune systems should not obtain rodents
for pets.

What
should I do if I no longer want my pet rodent?

People who have already
purchased hamsters or other rodents from pet stores should not return
their animals to the stores, regardless of where the animal was purchased.
People who no longer wish to keep their pet rodent should consult a veterinarian.

Can
I release my pet rodent into the wild?

No. Pet rodents
must not be released into the wild for humane reasons and because it is
illegal in many states. Pet rodents are not adapted to surviving in the
wild environment and may starve or be killed by predators. Many pet rodents
are not native species to North America. Releasing them into the wild
could introduce a non-native species that could become a pest, endanger
native species, or otherwise damage the normal ecosystem.

Can
I have my pet rodent tested for LCMV?

CDC does not recommend
testing individual pet rodents. Testing on live rodents can be inaccurate
and misleading. Always assume that pet animals are capable of transmitting
certain infectious diseases. Follow appropriate precautions as described
on CDC's Healthy
Pets Web site when handling any pets.

How
can I purchase a safe and healthy pet?

There is no way
to be absolutely sure that any pet animals are free of all infectious
diseases. Information on purchasing a healthy pet and general steps to
prevent pet rodents from bringing diseases into the home is available
at http://www.cdc.gov/healthypets/lcmv_rodents.htm.

Should
pregnant women be concerned about owning a hamster or other rodent?

LCMV infection during
pregnancy can cause severe illness or
developmental defects in the fetus. Women who are pregnant or who are
planning to become pregnant should avoid contact with all rodents. Some
of the following precautions can be taken to reduce the risk of acquiring
LCMV infection during pregnancy:

To avoid contact
with wild rodents, pregnant women who reside in a household with a wild
rodent infestation should have the infestation controlled promptly by
a professional pest control company or another member of the household.

To avoid contact
with pet rodents, remove the pet rodents from the house or keep pet
rodents in a separate part of the home. Pregnant women should ask another
family member or friend to clean the cage and care for the pet or arrange
for temporary adoption of the pet by a responsible person. Pregnant
women should avoid any room where a rodent resides.

Should
people with weakened immune systems be concerned about owning a hamster
or other rodent?

People with an impaired
immune system may be at risk for more severe disease from LCMV and other
diseases carried by pet rodents. Persons with an impaired immune system
should avoid contact with all rodents.

Can
I get tested for LCMV?

Testing for LCMV
infection in persons who have no symptoms is not necessary. Individuals
who are experiencing symptoms as described above should seek medical care
and let the physician know about any exposures to wild or pet rodents.
Only your physician can decide whether testing for LCMV is necessary

What
is being done to prevent LCMV infection in pet rodents?

CDC and other partners are working with breeders and retailers in the
pet industry to minimize the risk of LCMV infection in rodents that are
sold to the public and to educate owners of pet rodents about LCMV infection.
For more information on what your state is doing regarding LCMV, please
contact
your state health department or visit their Web site.